Faculty of Sciencehttp://hdl.handle.net/10311/16
Thu, 13 Dec 2018 09:43:10 GMT2018-12-13T09:43:10ZAnalysis of genetic diversity of Cercospora beticola isolates from Swiss chard in Southern Botswanahttp://hdl.handle.net/10311/1870
Analysis of genetic diversity of Cercospora beticola isolates from Swiss chard in Southern Botswana
Utlwang, Rebecca; Loeto, Daniel; Khare, Krishna B.; Wale, Kabo R.; Khonga, Elenimo B.; Segwagwe, Amogelang T.; Letsholo, Baemedi
Cercospora Leaf Spot (CLS) of Swiss chard (Beta vulgaris L. var. cicla) remains an important foliar disease
worldwide, yet the causative agent Cercospora beticola genetic variability remains incompletely understood in Botswana. To assess the diversity of C. beticola from diseased Swiss chard in southern Botswana, 78 isolates from two farms were analyzed. C. beticola was isolated from Swiss chard at very high frequencies from both Bokaa (91%) and Glen Valley (86%) farms. However, statistical analyses indicated that the isolation rate of the pathogen was not affected by the sampling location (p=0.01, p>0.01). Phylogenetic analyses revealed that the 18 sequenced C. beticola isolates clustered into four major classes, which could not be differentiated by the sampling location. Similarly, genetic analysis revealed high genetic diversity of C. beticola strains from the two farms, accounted for by within population diversity (greatest pairwise distance=0.004). The results presented herein underscore the importance of assessment of genetic diversity of pathogens which may be important in targeted control and management of plant diseases.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10311/18702018-01-01T00:00:00ZAntibacterial and antioxidant potential of Albizia anthelmintica as a medicinal plant on pathogenic veterinary isolateshttp://hdl.handle.net/10311/1851
Antibacterial and antioxidant potential of Albizia anthelmintica as a medicinal plant on pathogenic veterinary isolates
Wale, Kabo; Kwape, Tebogo Elvis; Sethibe, Laurah; Gaobotse, Goabaone; Loeto, Daniel; Sethebe, Bongani
Albizia anthelmintica is a medicinal plant belonging to the Fabaceae family. It is widely used by
smallholder farmers and pastoralists to treat internal parasites in their livestock. This study aimed to
determine the antibacterial and antioxidant potential of A. anthelmintica on pathogenic veterinary
isolates. 100% hexane (He100), 100% chloroform (Ch100), 100% ethanol (E100), and 70% ethanol (E70)
extracts of the roots and barks of A. anthelmintica were tested against four bacterial strains
(Escherichia coli, Clostridium perfringens, Salmonella enterica serovar Typhimurium and Proteus
mirabilis). Thin layer chromatography- 2, 2-diphenyl-1- picryl hydrazyl (TLC-DPPH) assay was used to
examine antioxidant potential of extracts. Antimicrobial activity was determined using the disc diffusion
method and minimum inhibiting concentrations (MICs) values were determined using the micro-titre
broth-dilution method. At a concentration of 500 μg/ml, E70 roots extract showed the highest % DPPH
inhibition of 66.9%. Among the bark extracts, the highest free radical scavenging activity was observed
in E70 extracts with 58.9% DPPH inhibition. Phytochemical analysis of the plant extracts revealed the
presence of compounds which are known to exhibit medicinal properties such as tannins, terpenoids,
quinones, saponins and fatty acids phenols. E100 bark extracts contained most of these compounds
except flavonoids. Only alkaloids were not detected in any of the roots or bark extracts. Ch100 bark
extracts showed the highest antimicrobial activity and all bacterial isolates were resistant to the E100
root extracts. Ch100 root extracts showed the lowest minimum inhibition concentration of 0.625 mg/ml
against S. enterica serovar Typhimurium. Findings of this study show that some of the root and bark
extracts of the A. anthelmintica plant have both antimicrobial and antioxidant properties. These findings
can possibly be relevant in the development of novel medication against veterinary pathogens.
Furthermore, this study will guide similar studies.
Sat, 10 Nov 2018 00:00:00 GMThttp://hdl.handle.net/10311/18512018-11-10T00:00:00ZImpact of desertification on livelihoods in Katsina State, Nigeriahttp://hdl.handle.net/10311/1850
Impact of desertification on livelihoods in Katsina State, Nigeria
Saulawa, Bishir Gambo; Atlhopheng, Julius; Darkoh, Michael Bernard Kwesi; Mosetlhi, Bothepha
Is one of the overwhelming environmental problems in Katsina State where 75% of its nearly 6 million people on a 24,192 km2 of land depend on agriculture. Few studies have been undertaken to enhance the state of knowledge of the consequences of desertification in this area. As a result, anecdotal data has been relied upon in making an assessment and often policy formulations. It was against this background that the study sought to assess the perceived impact of desertification on livelihoods in Katsina State. A total of 385 randomly selected farming families from across the three agro-ecological zones of Katsina State and 29 key informants were interviewed on the impact of desertification on livelihoods in the State. The data obtained were analysed using frequencies, logistic regression and Chi-square as well as contextual analysis.The study established that the impact of desertification on livelihoods included major effects on pastoralism and rain-fed crop production through degradation of pastoral areas and reduction in crop yields. Desertification also amplified conflicts between the farming families and the Fulani herders. Desertification was further revealed to have influenced migration to urban centres and accelerated out-migration to other countries. As a result of desertification, forest reserves have diminished through deforestation and conversion to farmlands by the farming families. Desertification has also promoted bush encroachment and the disappearance of palatable grass species. Contrary to the generalized views, the loss of farmland, abandoned settlements and dried up wells were found to be uncommon in the study area. The result of this study concretizes the central statement of the study that impact of desertification is site-specific, and each location requires its independent analysis before a conclusion can be reached.
Fri, 01 Jun 2018 00:00:00 GMThttp://hdl.handle.net/10311/18502018-06-01T00:00:00ZLand use, rangeland degradation and ecological changes in the southern Kalahari, Botswanahttp://hdl.handle.net/10311/1849
Land use, rangeland degradation and ecological changes in the southern Kalahari, Botswana
Dougill, Andrew J.; Akanyang, Lawrence; Perkins, Jeremy S.; Eckardt, Frank D.; Stringer, Lindsay C.; Favretto, Nicola; Atlhopheng, Julius; Mulale, Kutlwano
Dual‐scale analyses assessing farm‐scale patterns of ecological change and landscape‐scale patterns of change in vegetation cover and animal distribution are presented from ecological transect studies away from waterpoints, regional remotely sensed analysis of vegetation cover and animal numbers across the southern Kalahari, Botswana. Bush encroachment is prevalent in semi‐arid sites where Acacia mellifera Benth. is widespread in communal areas and private ranches, showing that land tenure changes over the last 40 years have not avoided rangeland degradation. Herbaceous cover is dominated in intensively grazed areas by the annual grass Schmidtia kalahariensis Stent and in moderately grazed areas by the perennial grass Eragrostis lehmanniana Nees. Nutritious perennial grass species including Eragrostis pallens Hack. Ex Schinz remain prevalent in Wildlife Management Areas. Other ecological changes include the invasion of the exotic Prosopis glandulosa Torr. and dense stands of Rhigozum trichotomum Kuntze. in the arid southwest. Regional patterns of wildlife species show that the expansion of cattleposts and fenced ranches has led to large areas of low wildlife conservation value even in areas where cattle production is not practiced. Findings show the need for integrated landscape‐scale planning of land use if the ecological value and biodiversity of the southern Kalahari is to be retained.
Tue, 09 Feb 2016 00:00:00 GMThttp://hdl.handle.net/10311/18492016-02-09T00:00:00Z